Billionaire entrepreneur Richard Branson on Saturday vowed to find out what caused his space tourism company’s passenger spaceship to crash during a test flight, killing one pilot and injuring the other, but expressed a desire to press on with the dream of commercial space flight.

Michael Alsbury, 39, has been identified as the pilot who died in the crash of Virgin Galactic SpaceShipTwo, and the surviving pilot is Peter Siebold, 43, the Kern County Sheriff’s Office said in a statement.

Branson arrived in California’s Mojave Desert to meet his Virgin Galactic team and federal officials who were opening their investigation into Friday’s accident, the second in less than a week involving a commercial space company.

Virgin Galactic’s SpaceShipTwo went down during a powered test flight, scattering debris over the Mojave Desert, 95 miles (150 km) north of Los Angeles.

“We owe it to our pilots to find out exactly what went wrong,” Branson said during a news conference in Mojave.

“If we can overcome it, we will make absolutely certain that the dream lives on,” he said.

Alsbury, who a sheriff’s spokesman said was from Tehachapi, California, was a project engineer and test pilot at Scaled Composites, a Northrop Grumman Corp NOC.N subsidiary that built and designed the spacecraft for Virgin Galactic.

Siebold was piloting SpaceShipTwo on Friday and Alsbury was serving as co-pilot, Scaled Composites said in a statement. Alsbury was flying for the ninth time aboard SpaceShipTwo, including serving as the co-pilot on its first rocket-powered test flight on April 29, 2013, according to his biography on the company’s website.

He was found dead in the aircraft, Kern County Sheriff Donny Youngblood said on Friday.

Siebold parachuted from SpaceShipTwo and was found a mile from the fuselage, Youngblood said. He had moderate to major injuries and was taken by helicopter to Antelope Valley Hospital, the Sheriff’s Office said in a statement. He was alert and talking with his family and doctors on Saturday, the statement from Scaled Composites said. He had been the pilot alongside Alsbury on SpaceShipTwo’s maiden test flight last year, according to the company’s website.

A team of investigators from the National Transportation Safety Board arrived at the crash site on Saturday to begin piecing together what led to the accident.

“This was a test flight, and test flights are typically very well documented in terms of data,” said Christopher Hart, acting chairman of the NTSB. “We may have lots of evidence that will help us with the investigative process,” he said.

Friday’s crash was the second disaster in less than a week suffered by a private space company, dealing a blow to the fledgling commercial space industry that has been taking on work traditionally done by governments.

On Tuesday, an Antares rocket built and launched by Orbital Sciences Corp ORB.N exploded after liftoff from Wallops Island, Virginia, destroying a cargo ship bound for the International Space Station.

NEW TYPE of FUEL

The Virgin probe will likely focus on SpaceShipTwo’s rocket engine, which on Friday was flying with a new type of fuel for the first time, experts said.

The solid plastic-type propellant is ignited by nitrous oxide, commonly known as laughing gas.

Virgin Galactic announced in May that it was replacing the rubber-based propellant used during the spaceship’s three previous rocket-powered test flights to get better performance.

“We’ve tested both of these fuel grains a lot,” Virgin Galactic chief executive George Whitesides told Reuters at the time.

Before Friday’s flight, SpaceShipTwo’s last powered test flight was in January, though the rocket and its new propellant had passed multiple ground tests.

Virgin Galactic is a U.S. offshoot of the London-based Virgin Group founded by Branson, one of the world’s most famous entrepreneurs whose business empire ranges from airlines to music stores and mobiles phones.